Vinyl acetate-ethylene-n-methylol acrylamide interpolymer latex and woven fabrics coated thereby



United States Patent 3,345,318 VINYL ACETATE ETHYLENE N METHYLOLACRYLAMHDE INTERPGLYMER LATEX AND WOVEN FABRICS COATED THEREBY Martin K.Lindemann, Somerville, and Rocco P. Volpe, Newark, N..l., assignors, bymesne assignments, to Air Reduction Company, Incorporated, New York,N.Y., a corporation of New York No Drawing. Filed Mar. 31, 1965, Ser.No. 444,375 6 Claims. (Cl. 26029.6)

This invention relates to the treatment of woven fabrics and is moreparticularly concerned with the application to woven fabrics of awater-resistant and solvent-resistant coating finish to improve the bodyand drape of the fabrics.

The coating, e.g. back coating, and finishing of woven fabrics arewell-known operations and various compositions for such use have beenproposed and are used in practice. However, it is important, for optimumresults, that the coating or finish applied be water-resistant andsolvent-resistant and that it adhere firmly to the fibers of the wovenfabric so that it will not be removed from the woven fabrics when theyare washed or dry cleaned, and it is desired to have coating orfinishing agents which will remain on the woven fabrics and will beeffective for their intended purposes through many washing or cleaningcycles. Attempts to meet these requirements has ioften involved theprovision of relatively complex and expensive compositions whichnecessarily increase the cost of the finished product.

It is accordingly an object of this invention to provide new, improvedcompositions for application to woven fabrics.

It is a further object of the present invention to provide a polymericcoating which, when applied to woven fabrics, gives the desiredcharacter to the fabrics, yet which is highly resistant to washing andcleaning and, at the same time, is economically attractive.

In accordance with the present invention, woven fabrics, whether formedfrom natural fibers such as cotton, wool, linen and the like, or fromsynthetic fibers such as cellulose acetate, nylon, Dacron, and the like,or of mixtures of natural and/ or synthetic fibers, are given adesirable body and drape by applying to them a polymeric latex havingcharacteristics which will be described below and drying the latex toremove its liquid component and to leave upon the woven fabrics adeposit of a water-resistant and solvent-resistant polymeric coating.

The latex used in accordance with the invention contains as thepolymeric component an interpolymer of vinyl acetate and ethylenecopolymerized with N-methylol acrylamide which is effective topolymerize and to crosslink with the initial vinyl acetate and ethylenecontaining interpolymer under the action of heat. The abovedescribedcomposition is applied to the woven fabric web in the form of an aqueouslatex containing the interpolymer of vinyl acetate, ethylene andcopolymerized N- methylol acrylamide in the dispersed phase. The vinylacetate-ethylene-N-methylol acrylamide interpolymer is characterized byan ethylene content of to 40%, preferably 16 to 40%, a particle size of0.1 to 2 preferably 0.1 to 0.25 and an intrinsic viscosity of 1 to 2.5dl./g. The amount of N-methylol acrylamide is 0.5 to 10% on the vinylacetate.

The composition is readily prepared by the interpolymerization of vinylacetate, ethylene and N-methylol acrylamide in an aqueous dispersionsystem. The N-methylol acrylamide readily copolymerizes with the vinylacetate and the ethylene to form an interpolymer or'terpolymer but, asmentioned, is adapted to undergo further reaction after this initialpolymerization upon the application of ing agent, at a pH of 2 to 6, thecatalyst being added incrementally. The process is a batch process whichinvolves first a homogenization period in which the vinyl acetatesuspended in water is thoroughly agitated in the presence of ethyleneunder the working pressure to effect solution of the ethylene in thevinyl acetate up to the substantial limit of its solubility under theconditions existing in the reaction zone, while the vinyl acetate isgradually heated to polymerization temperature. The homogenizationperiod is followed by a polymerization period during which the catalyst,which consists of a main catalyst or initiator, and may include anactivator, is added incrementally, and the N-methylol acrylamide issimilarly added incrementally, the pressure in the system beingmaintained substantially constant by application of a constant ethylenepressure.

Various free-radical forming catalysts can be used in carrying out thepolymerization of the monomers, such as peroxide compounds. Combinationtype catalysts employing both reducing agents and oxidizing agents canalso be used. The use of this type of combined catalyst is generallyreferred to in the art as redox polymerization or redox system. Thereducing agent is also often referred to as an activator and theoxidizing agen as an initiator. Suitable reducing agents or activatorsinclude bisulfites, sulfoxylates, or other compounds having reducingproperties such as ferrous salts, and tertiary aromatic amines, e.g.N,N-dimethyl aniline. The oxidizing agents or initiators includehydrogen peroxide, organic peroxides such as benzoyl peroxide, t-butylhydroperoxide and the like, persulfates, such as ammonium or potassiumpersulfate, perborates, and the like. Specific combination typecatalysts or redox systems which can be used include hydrogen peroxideand zinc formaldehyde sulfoxylate; hydrogen peroxide, ammoniumpersulfate, or potassium persulfate, with sodium metabisulfite, sodiumbisulfite, ferrous sulfate, dimethyl aniline, zinc formaldehyde:sulfoxylate or sodium formaldehyde sulfoxylate, Other types ofcatalysts that are well-known in the art can also be used to polymerizethe monomers, such as the peroxide compounds, with or without theaddition of reducing agents or other activating materials. It isadvantageous to utilize more water-soluble peroxides, such as hydrogenperoxide, rather than the more oil-soluble peroxides such as t-butylhydroperoxide, in the redox system, to catalyze the monomerpolymerization. Redox catalyst systems are described, for example, inFundamental Principles of Polymerization by G. F. DAlelio (John Wileyand Sons, Inc., New York, 1952) pp. 333 et seq. Other types of catalyststhat are well known in the art can also be used to polymerize themonomers according to this invention, with or without the addition ofreducing agents or other activating materials.

The catalyst is employed in the amount of 0.1 to 2%, preferably 0.25 to0.75%, based on the weight of vinyl acetate introduced into the system.The activator is ordinarily added in aqueous solution and the amount ofactivator is generally 0.25 to 1 times the amount of catalyst.

,The emulsifying agents which are suitably used are non-ionic. Suitablenon-ionicemulsifying 1 agents include polyoxyethylene condensates.Polyoxyethylene condensates may be represented by the general formula:

where R is the residue of a fatty alcohol containing 10-18 carbon atoms,an alkyl phenol, a fatty acid containing 10-18 carbon atoms, an amide,an amine, or a mercaptan, and where n is an integer of 1 or above. Somespecific examples of polyoxyethylene condensates which can be usedinclude polyoxyethylene aliphatic ethers such as polyoxyethylene laurylether, polyoxyethylene oleyl ether, polyoxyethylene hydroabietyl etherand the like; polyoxyethylene alkaryl ethers such as polyoxyethylenenonylphenyl ether, polyoxyethylene octylphenyl ether and the like;polyoxyethylene esters of higher fatty acids such as polyoxyethylenelaurate, polyoxyethylene oleate and the like as well as condensates ofethylene oxide with resin acids and tall oil acids; polyoxyethyleneamide and amine condensates such as N-polyoxyethylene lauramide, andN-lauryl-N-polyoxyethylene amine and the like; and polyoxyethylenethio-ethers such as polyoxyethylene ndodecyl thio-ether.

The non-ionic emulsifying agents which can be used according to thisinvention also include a series of surface active agents known asPluronics. The Pluronics have the general formula:

where a, b, and c are integers of 1 or above. As b increases, thecompounds become less water soluble or more oil soluble and thus morehydrophobic when a and remain substantially constant.

In addition, highly suitable are a series of ethylene oxide adducts ofacetylenic glycols sold commercially under the name Surfynois. Thisclass of compounds can be represented by the formula in which R and Rare alkyl radicals containing from 3 to carbon atoms, R and R areselected from the group consisting of methyl and ethyl, x and y have asum in the range of 3 to 60, inclusive.

' Some examples of non-ionic emulsifying agents which can be used are asfollows:

A polyoxyethylene nonylphenyl ether having a cloud point of between 126and 133 F. is marked under the trade name Igepal CO-630 and apolyoxyethylene nonylphenyl ether having a cloud point above 212 F. ismarketed under the trade name Igepal CO-887. A similar polyoxyethylenenonylphenyl ether having a cloud point of about 86 F. is marketed underthe trade name Igepal CO610. A polyoxyethylene octylphenyl ether havinga cloud point of between 80 F. and 160 F. is marketed under the tradename Triton X-100." A polyoxyethylene oleyl ether having a cloud pointof between 80 F. and 160 F. is marketed under the trade named AtlasG-39l5 and a polyoxyethylene lauryl ether having a cloud point above 190F. is marketed under the trade name Brij 35.

A polyoxypropylene having a cloud point of about 140 F. is marketedunder the trade name Pluronic L-64, and a polyoxypropylene having acloud point of about 212 F. is marketed under the trade name PluronicF-68. Pulr-onic L-64 is a polyoxyethylene-polyoxypropylene glycolconforming to the above general formula for Pluronics in which thepolyoxypropylene chain has a molecular weight of 1500 to 1800 and thepolyoxyethylene content is from 40 to 50 percent of the total weight ofthe molecule. Pluronic F-68 is a polyoxyethylene-polyoxypr-opyleneglycol con-forming to the above general formula for 'Pluronics in whichthe polyoxypropylene chain has a molecular weight of 1500 to 1800 andthe polyoxyethylene content is from 80 to 90 percent of the total weightof the molecule. The polyoxypropylene Pluronics are obtained bycondensing ethylene oxide on the polyoxypropylene base and thehydrophobichydrophilic nature of the resulting compound is controlled byvarying the molecular weight of either the hydrophobic base or thehydrophilic portion of the molecule.

Representative of the Surfynols are Surfynol 465 which is an ethyleneoxide adduct of 2,4,7,9-tetramethyl decynediol containing an average of10 moles of ethylene oxide per mole, and Surfynol 485 which correspondsto Surfynol 465 but contains an average of 30 moles of ethylene oxideper mole. Surfynol 465 has a cloud point of about F. and Surfynol 485has a cloud point above 212 F.

In the foregoing, cloud points recited are based on 1% aqueoussolutions. A single emulsifying agent can be used, or the emulsifyingagents can be used in combination. When combinations of emulsifyingagents are used, it is advantageous to use a relatively hydrophobicemulsifying agent in combination with a relatively hydrophilic agent. Arelatively hydrophobic agent is one having a cloud point in 1% aqueoussolution below F. and a relatively hydrophilic agent is one having acloud point in 1% aqueous solution of 190 F. or above.

The concentration range of the total amount of emulsifying agents usefulis from 0.5 to 5% based on the aqueous phase of the latex regardless ofthe solids content. Latex stabilizers are also advantageously used. Thestabilizers employed are, in part, governed by the use to which thecopolymer latex is to be put, and/ or the particle size of thecopolymer. For example, the vinyl acetate ethylene copolymer laticesprepared by the method described can have various average particle sizeranges. When the latices are to have a small average particle size, e.g.below 025 as preferred in the present invention, anethylenically-unsaturated acid having up to 6 carbon atoms, isadvantageously used as the stabilizer. Typical acids of this characterare acrylic acid, methacrylic acid, itaconic acid, maleic acid, vinylsulfonic acid and the like. These unsaturated acids impart increasedstability to the latices. They tend to copolymerize with the monomers inthe system. The amount of unsaturated acid used is suitably 0.1 to 3%based on vinyl acetate, preferably 0.2 to 1%.

On the other hand, When the latex has an average particle size above025a, a protective colloid can be used in the polymerization mixture asthe stabilizing agent, although an unsaturated acid can be used ifdesired. Various amounts of colloids can be incorporated into thelatices as desired, but it is preferred to maintain the colloidconcentration at the lowest level possible. The amount of colloid usedwill also depend upon the particular colloid employed. Colloids ofhigher molecular Weight tend to produce a latex of a higher viscositythan like amounts of a lower molecular weight colloid. Other propertiesof the colloids aside from their molecular weight also affect theviscosity of the latices and also the properties of the films formedtherefrom. It is advantageous to maintain the colloid content of thelatices between about 0.05 and 2% by weight based on the total latex,and that hydroxyethyl cellulose is a particularly advantageous colloidwhen used in the latices.

Various other colloids can also be used, including polyvinyl alcohol,partially-acetylated polyvinyl alcohol, e.g. up to 50% acetylated,casein, hydroxyethyl starch, carboxymethyl cellulose, gum arabic, andthe like, as known in the art of synthetic polymer latex technology.

In order to maintain the pH of the system at the desired value, there issuitably added an alkaline buffering agent of any convenient type. Anyalkaline material which is compatible with the stabilizing agent can beused as the buffer. The amount of buffer is that sufiicient to adjustthe pH of the system within the desired range. Am monium and sodiumbicarbonate are preferred buffer because of their compatibility with thesystem and their low cost. The amount of buffer is generally about 0.1to 0.5% by weight, based on the monomers. Other buffers such as disodiumphosphate, sodium acetate, and the like, can, however, also be used.

One of the features of the method described above is that latices ofrelatively high solids contents can be directly produced and thus theproducts generally have, as produced, solids contents of 45 to 60%. Theycan, of course, be easily thinned by the addition of Water to lowersolids contents of any desired value.

Lower reaction temperatures for polymerizing vinyl acetate than haveheretofore been feasible economically can also be used. The use of lowerreaction temperatures has been found to result in higher molecularweight vinyl acetate copolymers. The reaction temperature can becontrolled by the rate of catalyst addition and by the rate of the heatdissipation therefrom. Generally we have found that it is advantageousto maintain a mean temperature of about 50 C. during the polymerizationof the monomers and to avoid temperatures much in excess of 80 C. Whiletemperatures as low as 0 can be used, economically the lower temperaturelimit is about30 C.

The reaction time will also vary depending upon other variables such asthe temperature, the catalyst, and the desired extent of thepolymerization. It is generally desirable to continue the reaction untilless than 0.5% of the vinyl acetate and N-methylol acrylamide remainsunreacted. Under these circumstances, a reaction time of about 6 hourshas been found to be generally sufficient for complete polymerization,but reaction times ranging from 3 to 10 hours have been used, and otherreaction times can be employed, if desired.

In carrying out the polymerization, a substantial amount of the vinylacetate is initially charged to the polymerization vessel and saturatedwith ethylene in the manner discussed above. Most advantageously, atleast about 75% of the total vinyl acetate to be polymerized isinitially charged, preferably at least about 85%, and the remainder ofthe vinyl acetate is incrementally added during the course of thepolymerization. The charging of all of the vinyl acetate initially isalso contemplated, with no additional incremental supply. When referenceis made to incremental addition, whether of vinyl acetate, N- methylol,acrylamide, catalyst, or activator, substantially uniform additions,both with respect to quantity and time, are contemplated.

The quantity of ethylene entering into the copolymer is influenced bythe pressure, the agitation, and the viscosity of the polymerizationmedium. Thus, to increase the ethylene content of the copolymer, higherpressures are employed, but even to introduce 40% or more of ethyleneinto the copolymer, pressures in excess of 100 atms. are not required.However, a pressure of at least about 10 atms. is most suitablyemployed. Similarly, when high ethylene contents are desired, a highdegree of agitation should be employed, and high viscosities should beavoided, a low viscosity being preferred. When referring to viscosities,a viscosity of 30 to 150 centipoises is con sidered a low viscosity, aviscosity of 151 to 800 centipoises is considered a medium viscosity,and a viscosity of 801 to 3000 centipoises is considered a highviscosity.

The process of forming the vinyl acetate-ethylene-N- methylol acrylamideinterpolymer latices generally com prises the preparation of an aqueoussolution containing at least some of the emulsifying agent andstabilizer, and the pH bufiering system. This aqueous solution and theinitial charge of vinyl acetate are added to the polymerization vesseland ethylene pressure is applied to the desired value. As previouslymentioned, the mixture is thoroughly agitated to dissolve ethylene inthe vinyl acetate and in the water phase, agitation being continueduntil substantial equilibrium is achieved. This generally requires aboutminutes. However, less time may be required depending upon the vessel,the efficiency of agitation, the

6 specific system, and the like. In any case, by measuring the pressuredrop of the ethylene in conventional manner, the realization ofsubstantial equilibrium can be easily determined. Conveniently thecharge is brought to polymerization temperature during this agitationperiod. Agitaton can be effected by shaking, by means of an agitator, orother known mechanism. The polymerization is then initiated byintroducing initial amounts of the catalyst, and of the activator whenused. After polymerization has started, the catalyst and the activatorare incrementally added as required to continue polymerization, and theN-methylol acrylamide and the remaining vinyl acetate, if any, issimilary added.

As mentioned, the reaction is generally continued until the residualvinyl acetate and N-methylol acrylamide content is below 0.5%. Thecompleted reaction product is then allowed to cool to about roomtemperature, while sealed from the atmosphere. The pH is then suitablyadjusted to a value in the range of 4.5 to 7, preferably 6 to 6.5 toinsure maximum stability.

The particle size of the latex can be regulated by the quantity ofnon-ionic emulsifying agent or agents employed and by the use or nonuseof a colloidal stabilizing agent. Thus, to obtain smaller particlesizes, greater amounts of emulsifying agent are used and colloidalstabilizing agents are not employed. For example, to pro vide' averageparticle sizes below about 025 the total amount of non-ionic emulsifyingagent should be at least about 2%, based on the aqueous phase of thelatex, and no colloidal stabilizing agent should be used, or if acolloidal stabilizing agent is used, only very small amounts should beemployed.

On the other hand, when particle sizes of 025 and above are desired, atmost about 2% of total emulsifying agent based on the aqueous phase ofthe latex should be used, and a colloidal stabilizing agent should beincluded in the amounts previously indicated. As a general rule,

the smaller the amount of emulsifying agent employedand the greater theamount of colloidal stabilizing agent included in' the latex system, thegreater the average particle size. Conversely, the greater the amount ofthe emulsifying agent employed and the smaller the amount of colloidalstabilizing agent use, including the total absence of the latter, thesmaller the average particle size. It will be understood that in eachcase, the quantity and size values referred to above are all within theranges of values previously specified.

' By following the procedure described above, particularly the initialsaturation of the polymerizationmixture With ethylene beforepolymerization is'initiated, there can be produced the stable vinylacetate-ethylene-N- methylol acrylamide interpolymer latex characterizedabove, with the copolymer having an ethylene content of 5 to 40%, anintrinsic viscosity of l to 2.5 dl./g., and an average particle size of0.1 to 2 and the latex having a high solids content of up to 60% ormore.

The ethylene content can be determined by means of the saponificationnumber.

Intrinsic viscosity is suitably determined by conventional techniques,i.g. in accordance with the procedure described on pages 309-314 ofPrinciples of Polymer Chemistry by Paul J. Flory (Cornell UniversityPress- 1963); using an Ubbelohde (suspended level) viscometer at 30 C.

The vinyl acetate-ethylene-N-methylol acrylamide interpolymer latexdescribed above is readily applied to a woven fabric to provide aback-coating or similar coating which will give body, 'or fullness, ordrape, or like desirable characteristics, to the fabric, e.g. anupholstery fabric, by conventional coating means employed in the wovenfabric art. Particularly suitable for application of the latex to-thewoven fabric is the socalled licker-on apparatus, wherein a troughcontains the latex to be applied and is fitted with a rotatable roll,which is partially immersed in the latex. The fabric to be coated ispassedacross the 7 upper portion of the roll which is above the level ofthe latex in the trough but carries a film or coating of the latex whichis transferred to the woven fabric in conventional manner. Conventionalspray apparatus may also be employed, or the latex may be applied in anyother convenient manner.

The latex is suitably at a temperature of the order of 120 to 140 F.while it is in the licker-on trough and is being applied to the fabric.The rate of application can be readily controlled in known manner andthe quantity applied to the fabric will depend upon individualconditions and the individual fabric being treated. Ordinarily, forservice as a back-coating, the latex is applied at such a rate that thesolids content of the coating is of the order of -6% based on the weightof the fabric. The solids content of the latex itself can also vary, butit is generally advantageous to have a solids content of the order of50%. If the latex, as produced, has a higher solids content, or if aneven lower solids content is desired, the appropriate solids content canreadily be attained by appropriate dilution of the latex with water.

After the coating has been applied, the fabric is subjected to a dryingstage and a curing stage. The drying stage is ordinarily carried out ata temperature of the order of 240 to 250 F. for a period of time of theorder of 2 minutes, and the curing stage is conveniently carried out ata temperature in the neighborhood of 300 to 300 F. for a period of timeof the order of 3 minutes. However, other time-temperature relationshipcan be employed, as is well known in the art, shorter times at highertemperatures or longer times at lower temperatures being used. Forexample, the curing step can be carried out at 280 F. for about min. ormore. However, economic considerations make the use of excessively longtimes undesirable, and the upper temperature limit is governed by thenature of the fabric. Temperatures which degrade the fabric are, ofcourse, avoided. However, if the fabrics are heat resistant,temperatures as high as 350 F. or higher can be used with times of 5-10min. or more. If desired, the drying and curing can be effected in asingle exposure or step, e.g. at 300 F. for 5-l0 min. In the curing, theN-methylol acrylamide completes its polymerization and cross-links inthe resin. To facilitate this postpolymerization, the latex has mixedwith it, before it is applied to the fabric, a suitable catalyst for theN-methylol acrylamide. Thus, acid catalysts such as mineral acids, e.g.HCl, or organic acids, e.g. oxalic acid, or acid salts such as ammoniumchloride, are suitably used, as known in the art. The amount of catalyst.is generally about 0.5 to 2% of the total resin.

Woven fabrics coated with the resinous latex described above exhibit thedesirable characteristics indicated, and retain these characteristics,since the polymeric coating deposited from the latex will withstandnumerous contacts with water or dry cleaning solvents, e.g. chlorinatedhydrocarbons.

The following examples are given to illustrate the present invention,but it will be understood that they are intended to be illustrative onlyand not limitative of the invention. In the examples, all parts are byweight unless otherwise indicated.

Example 1 The following was charged to a 25 gal. stainless steelpressure reactor equipped with temperature controls and After purgingwith nitrogen and ethylene, 104 g. potassium persulfate was added to themixture. The agitator was set at 300 rpm. and the kettle pressurizedwith ethyl cue to 40 atm. After reaching equilibrium and after heatingto 50 C. the agitation was reduced to 195 r.p.m. and polymerization wasstarted by adding 20 cc. of a 0.5% solution of Formopon. During thepolymerization 2,400 g. of a 60% aqueous solution of N-inethylolacrylamide was added incrementally, in addition to 136 g. of potassiumsulfate which was also added incrementally as needed. The polymerizationwas complete after 4 /2 hrs. The latex was cooled and neutralized withammonia to a pH of 5. The latex had the following properties:

Solids percent 43.2 Ethylene in copolymer do 117 T C.... +1 T, c +10Intrinsic viscosity 0.49 Particle size 0.2;1.

Methanol, 30 C.

The above-described latex was diluted to 10% solids, 2.5% of ammoniumchloride (based on the weight of solids) was added, and the latex wasapplied to an x 80 print cloth fabric. The latex was applied at the rateof about 18% (solids) based on the weight of the fabric. The fabric wasthen dried and cured on a pin frame at 300 F. for about 6 min.

The cured fabric was then subjected to a 1-hr. accelerated washing testat a temperature of 160 F., employing an AATCC Launder-Ometer, inaccordance with Standard Test Method 61-1962 as set forth on pages B-76and B-77 of the 1962 Technical Manual of the American Association ofTextile Chemists and Colorists, with the sample being tumbled in astainless steel cylinder containing stainless steel balls and the washsolution. The coating was found to be completely intact after theWashing operation.

Example 2 The above-described procedure with respect to the preparationof a treated fabric were repeated, except that the coating used was avinyl acetate homopolymer latex initially having a solids content of48.7 and a pH of 66.5. At the end of the washing test, the fabricretained only a portion of the coating and had failed the test.

In the characterization of the interpolymer of Example 1, T is thetemperature at which the torsional modulus is 135,000 lbs./in. and T thetemperature at which the torsional modulus is 10,000 lbs/in. determinedaccording to ASTM-Dl043-61T.

It will be apparent that various changes and modifications may be madein the embodiments of the invention described above, without departingfrom the scope of the invention, as defined in the appended claims, andit is intended, therefore, that all matter contained in the foregoingdescription shall be interpreted as illustrative only and not aslimitative of the invention.

We claim:

1. A coated woven fabric having on at least one face thereof a coatingcomprising an interpolymer of vinyl acetate-ethylene-N-methylolacrylamide, the ethylene in said interpolymer being, beforepolymerization, unsubstituted monomeric ethylene and said interpolymercontaining 5 to 40% by weight ethylene and the amount of N-methylolacryamide being 0.5 to 10% by weight of the vinyl acetate.

2. In the preparation of a coated woven fabric wherein the woven fabricis coated by applying to at least one face thereof a coating resin in avolatile liquid and then heating to remove the liquid, the improvementwhich comprises applying in an aqueous medium a coating resin dispersedin said medium consisting essentially of an interpolymer of vinylacetate-ethylene-N-methylol acrylamide, the ethylene in saidinterpolymer being, before polymerization, unsubstituted monomericethylene and said interpolymer containing 5 to 40% by weight ethyleneand the amount of N-methylol acrylamide being 0.5 to 10% by weight ofthe vinyl acetate.

3. A coated woven fabric having on at least one face thereof a coatingdeposited from a vinyl acetate-ethylene- N-methylol acnyla-rnideinterpolymer latex comprising an aqueous medium having colloidallysuspended therein a vinyl acetate-ethylene-N-methylol acrylamideinterpolymer, the ethylene in said interpolymer being, beforepolymerization, unsubstituted monomeric ethylene and said interpolymercontaining to 40% by weight ethylene and the amount of N-methylolacrylamide being 0.5 to by weight of the vinyl acetate.

4. A coated woven fabric as defined in claim 3 wherein said vinylacetate-ethy1ene-N-methylol acnylamide interpolymer has a particle sizeof 0.1 ,u to 2 5. A latex composition effective for application to awoven fabric to form a resin coating thereon comprising an aqueousmedium having colloidally suspended therein a vinylacetate-ethylene-N-methylol acrylamide interpolymer, the ethylene insaid interpolymer being, before 10 polymerization,'unsubstitutedmonomeric ethylene and, said interpolymer containing 5 to 40% by weightethylene and the amount of N-methylol acrylamide being 0.5 to 10% byweight of the vinyl acetate.

6. A composition as defined in claim 3 wherein said vinylacetate-ethylene-N-methylol acryla-mide interpolymer has a particle sizeof 0.1a to Zn.

References Cited UNITED STATES PATENTS 2,703,794 3/1955 Roedel 260-87.33,090,704 5/1963 Collins et al. 26029.6 3,118,852 1/1964 Christenson etal. 260834 3,137,589 6/1964 Reinhard et al 26029.6 3,301,809 1/1967Goldberg et a1. 26029.6

SAMUEL H. BLECH, Primary Examiner.

MURRAY TILLMAN, Examiner.

J. ZIEGLER, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,345,318 October 3, 1967 Martin K. Lindemann et al.

It is certified that error appears in the above identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 2, line 34, "agen" should read agent Column line 27, "HO(C H O)(C H O) (C H O) H" should read HO(C H O) [C H O) (C H O) H line 35,"Surfynois" should read Surfynols lines 37 to 40 the formula shouldappear as sh below:

H(OCH CH O (CH CH O) H same column 3, line 48, "marked" should readmarketed line 66, "Pulronic" should read Pluronic Column 6, line 60,"i.g." should read e.g. Column 7, line 29, "relationship should readrelationships Column 8, line 39, "procedure" should read proceduresColumn 10, line 5, claim reference numeral "3" should read 5 Signed andsealed this 20th day of October 1970.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting OfficerCommissioner of Patents

5. A LATEX COMPOSITION EFFCTIVE FOR APPLICATION TO A WOVEN FABRIC TOFORM A RESIN COATING THEREON COMPRISING AN AQUEOUS MEDIUMHAVINGCOLLOIDALLY SUSPENDED THEREIN A VINYL ACETATE-ETHYLENE-N-METHYLOLACRYLAMIDE INTERPOLYMER, THE ETHYLENE IN SAID INTERPOLYMER BEING, BEFOREPOLYMERIZATION, UNSUBSTITUTED MONOMERIC ETHYLENE AND, SAID INTERPOLYMERCONTAINING 5 TO 40% BY WEIGHT ETHYLENE AND THE AMOUNT OF N-METHYLOLACRYLAMIDE BEIGH 0.5 TO 10% BY WEIGHT OF THE VINYL ACETATE.